A different perspective.
Young children benefit most from treating them like people. Autonomous people.
The time you spend optimizing books and toys is time you don't spend on what matters.
Look at it this way, you will make some good choices, you will make some not so good choices, but most of your choices won't make a difference at all because they will be little choices and a child's life is more massive by many orders of magnitude.
I mean what is a kid? You're a decade or so away from puberty and the point where their friends become more influential than you. Picture books and plushy aesthetics are an ordinary flap of butterfly wings.
But don't worry you've got a decade to grow into the job and in ten years you will have a better perspective on what matters. And in two decades they will be adult kids and you will have a role in their adult scaled problems...assuming of course you are laying the groundwork for that.
Fortunately, you will have to make a concerted effort to screw that up (and unfortunately there are parents who do (no implying you are one of them)).
Sit on the floor and play beside your child, and with them sometimes, and against them as they get older. That's what matters to them and to you.
Sure someone may have written a master's thesis on the bullshit debate you are having because they needed to write a master's thesis in order to graduate. But there's no objective "kids benefit more" from X because X is one an infinite number of factors.
And because running a double blind long term study would be grossly unethical.
Good luck.